function resize_image($filename, $tmpname, $xmax, $ymax)    {        $ext = explode(".", $filename);        $ext = $ext[count($ext)-1];             if($ext == "jpg" || $ext == "jpeg")            $im = imagecreatefromjpeg($tmpname);        elseif($ext == "png")            $im = imagecreatefrompng($tmpname);        elseif($ext == "gif")            $im = imagecreatefromgif($tmpname);                 $x = imagesx($im);        $y = imagesy($im);                 if($x <= $xmax && $y <= $ymax)            return $im;             if($x >= $y) {            $newx = $xmax;            $newy = $newx * $y / $x;        }        else {            $newy = $ymax;            $newx = $x / $y * $newy;        }                 $im2 = imagecreatetruecolor($newx, $newy);        imagecopyresized($im2, $im, 0, 0, 0, 0, floor($newx), floor($newy), $x, $y);        return $im2;     }